[BUG] IPV6 DHCP-PD does not work with >64 prefixes on ASUSWRT

[sfx2000]

@john9527 and @RMerlin -- the efforts in this area are definitely appreciated by the community - Well done, and please continue to study the problem - hopefully some of this filters back up stream to eventually find it's way into the main code that Asus maintains.

It should be noted that all vendors are having some level of difficulty with IPv6, and the wide variety of options that the carriers have deployed make it an even more difficult task to cover all of those use cases.

 

[RMerlin]

John has a couple of fixes in his fork, did he push them back over to your repo?

Different architecture. John still uses radvd, while Asus and I now use dnsmasq + odhcp6c (developed by an OpenWRT guy).

I came through this by luck. I was just increasing allowed prefix lengths from 2 chars to 3 chars as per user requests, and while ensuring that all buffers were large enough to handle the extra byte, I saw that odd piece of code that didn't make any sense to me. After reviewing it with themiron, I decided to change it to something that made more sense.

 

[ankhazam]

Hello @RMerlin,
I flashed the 380_60_alpha3, set it up from scratch but still with negative result.
Please find the attached images:

 

[RMerlin]

Hello @RMerlin,
I flashed the 380_60_alpha3, set it up from scratch but still with negative result.
Please find the attached images:
View attachment 6601 View attachment 6603

You're suffering from a different issue then, it's not caused by the length of your prefix.

 

[ankhazam]

Any suggestions how to debug it? Turn off the ipv6 firewall? A 6to4 works ok... my ISP states that the router should resolve the wan gateway as prefix::2

 

[RMerlin]

Any suggestions how to debug it? Turn off the ipv6 firewall? A 6to4 works ok... my ISP states that the router should resolve the wan gateway as prefix::2

No idea, not an IPv6 expert. My ISP doesn't support it.

 

[ankhazam]

ok, cheers! thanks for the effort

 

[DataBitz]

My ISP has just enabled IPv6 and I seem to be having the same problem with not receiving a gateway address. My ISP is also providing /60
Did you ever resolve this?

 

[ankhazam]

Yes I 'solved' it... kinda...
If your ISP goes over PPPoE, then you have the same setup as mine.
1) you need to get your hands on the router's shell (telnet or SSH)
2) you need to add manually the default routing

In my case:
ip -6 route add 0::/0 dev ppp0
ip -6 route add default dev ppp0 metric 1
Of those is enough, though my knowledge of IPV6 is too low, to know how they differ

3) then you can check from that shell
ping -6 www.google.com

As I am not using SLAAC (causes Androids to go haywire -- crappy support for IPV6 stack) I use statefull setting and DHCPv6 doesn't announce my gateway to the clients.
Namely in e.g. windows I need to modify IPV6 settings for my adapter and add manually the gateway -- the WAN IPV6 address that you have hidden here

With SLAAC (aka stateless) adding the route on the router is enough.

GL:HF,
Ank

 

[cc24]

Yes I 'solved' it... kinda...
If your ISP goes over PPPoE, then you have the same setup as mine.
1) you need to get your hands on the router's shell (telnet or SSH)
2) you need to add manually the default routing

In my case:
ip -6 route add 0::/0 dev ppp0
ip -6 route add default dev ppp0 metric 1
Of those is enough, though my knowledge of IPV6 is too low, to know how they differ

3) then you can check from that shell
ping -6 www.google.com

As I am not using SLAAC (causes Androids to go haywire -- crappy support for IPV6 stack) I use statefull setting and DHCPv6 doesn't announce my gateway to the clients.
Namely in e.g. windows I need to modify IPV6 settings for my adapter and add manually the gateway -- the WAN IPV6 address that you have hidden here

With SLAAC (aka stateless) adding the route on the router is enough.

GL:HF,
Ank

This. I have had to just do the same to get IPv6 native to work. Pulled address details down ok from ISP but gateway was empty. LAN clients had correct IPv6 details but no internet connectivity.

Did this via SSH on the router, connectivity now working across the LAN (and router, ping6 failed there too for example):

ip -6 route add 0::/0 dev ppp0
ip -6 route add default dev ppp0 metric 1

RT-AC68U running 380.65_4

Is this a firmware bug or am I missing some where to set this up permanently in the GUI?

Edit: This is with a /64 btw

 

[cc24]

May be worth noting I have just looked at "ip -6 route show" and this lists both the route added with metric 1 and another with metric 1024:

default dev ppp0 metric 1 mtu 1492 advmss 1432 hoplimit 0
default dev ppp0 metric 1024 mtu 1492 advmss 1432 hoplimit 0

I can not remember what it was like before hand sorry. If I get a chance to reload things with out any one noticing I will and report back.

 

[DataBitz]

Yes I 'solved' it... kinda...
If your ISP goes over PPPoE, then you have the same setup as mine.
1) you need to get your hands on the router's shell (telnet or SSH)
2) you need to add manually the default routing

In my case:
ip -6 route add 0::/0 dev ppp0
ip -6 route add default dev ppp0 metric 1
Of those is enough, though my knowledge of IPV6 is too low, to know how they differ

3) then you can check from that shell
ping -6 www.google.com

As I am not using SLAAC (causes Androids to go haywire -- crappy support for IPV6 stack) I use statefull setting and DHCPv6 doesn't announce my gateway to the clients.
Namely in e.g. windows I need to modify IPV6 settings for my adapter and add manually the gateway -- the WAN IPV6 address that you have hidden here

With SLAAC (aka stateless) adding the route on the router is enough.

GL:HF,
Ank

Thanks for the update.
For me I had IPv6 set to use Ethernet instead of PPP. Once I changed this to PPP the gateway address came through correctly.

 

[cc24]

May be worth noting I have just looked at "ip -6 route show" and this lists both the route added with metric 1 and another with metric 1024:

default dev ppp0 metric 1 mtu 1492 advmss 1432 hoplimit 0
default dev ppp0 metric 1024 mtu 1492 advmss 1432 hoplimit 0

I can not remember what it was like before hand sorry. If I get a chance to reload things with out any one noticing I will and report back.

I've just disabled and re-enabled IPv6 native. No default routes show at all after enabling. Setting default route as before made it function again as before.

 

[cc24]

Set to PPP here.

 

[ankhazam]

Hey there Chief! (@RMerlin)
Could you please include this fix in Asuswrt-Merlin or maybe point us on how include the fix below, so that if the WAN IPv6 Gateway is missing after IPV6 connection initialization, then it would add the default route automatically?
It is a hassle having to ssh into the router and add manually each time the router relogs over PPPoE or reboots :/

Best regards,
Ank

Yes I 'solved' it... kinda...
If your ISP goes over PPPoE, then you have the same setup as mine.
1) you need to get your hands on the router's shell (telnet or SSH)
2) you need to add manually the default routing

In my case:
ip -6 route add 0::/0 dev ppp0
ip -6 route add default dev ppp0 metric 1
Of those is enough, though my knowledge of IPV6 is too low, to know how they differ

3) then you can check from that shell
ping -6 www.google.com

As I am not using SLAAC (causes Androids to go haywire -- crappy support for IPV6 stack) I use statefull setting and DHCPv6 doesn't announce my gateway to the clients.
Namely in e.g. windows I need to modify IPV6 settings for my adapter and add manually the gateway -- the WAN IPV6 address that you have hidden here

With SLAAC (aka stateless) adding the route on the router is enough.

GL:HF,
Ank

 

[cc24]

See this with a longer term fix until Asus fix it:
https://github.com/RMerl/asuswrt-merlin/issues/1360

 

[Gregory Phillips]

I could never get my router to obtain and keep an ipv address using dhcp on the stock firmware.

 

[ankhazam]

well with the script added according to the github issue everything works great on my part

 

[Gregory Phillips]

well with the script added according to the github issue everything works great on my part

Well if I run Merlin I don't have to do anything special except enjoy my IPv6 connection no matter how many times the router might be rebooted. I suppose you could look up the DNS server and manually enter it but I'll just stick to Merlin.

 

[Deleted member 22229]

Well if I run Merlin I don't have to do anything special except enjoy my IPv6 connection no matter how many times the router might be rebooted. I suppose you could look up the DNS server and manually enter it but I'll just stick to Merlin.

Strange Merlin's code changes nothing with IPv6 that im aware of. Im using stock Asus firmware there latest on my 3100 and IPv6 works great using native.